3x/0.5+9/2-(2.8-5x)/2=0

3x/0.5+9/2-(2.8-5x)/2=0

6x+4.5-1.4+2.5x=0
8.5x+3.1=0
8.5x=-3.1
X = (- 3.1) / 8.5 = 0.365

We know that the parabola y = a (X-H)? Has a maximum value when x = 2. The parabola passes through the point (1, - 3). We find the analytical formula of the parabola and point out that when x is the value, y increases with X

Given the parabola y = a (X-H), when x = 2, there is a maximum value. This parabola passes through the point (1, - 3), find the analytical formula of the parabola, and point out that when x is the value, y decreases with the increase of X

It is known that the parabola C: y = 2x ^ 2, the straight line y = KX + 2 intersects C at two points a and B, M is the midpoint of the line AB, and the vertical line passing through M as X axis intersects C at point n
I don't understand the abscissa of his "∩ n is K / 4
The derivation of the function y = 2x & sup2; gives y '= 4x
Therefore, the tangent slope of the parabola at n is k '= 4 × K / 4 = k "
If you take K / 4 in, don't you get y = k ^ 2 / 8? Why do you get y '= 4x

Tangent slope of curve y = f (x) at (x0, Y0) k = f '(x0)
So this problem is to substitute x = K / 4 into y '= 4x to find y' = k, which is the slope at N point

The equation of mathematics problem about meeting problem
The distance between the two places is 3630 meters. Party A and Party B travel from each other. Party A is 82 meters per minute. Party B is 83 meters per minute. They start for 15 minutes at the same time. How many minutes do they have to meet? Use the equation to solve

The distance between the two places is 3630 meters. Party A and Party B walk from each other. Party A walks 82 meters per minute and Party B walks 83 meters per minute. They have set out for 15 minutes at the same time. How many minutes can they meet?
(82 + 83) × 15 = 2475 (m)
3630-2475 = 1155 (m)
1155 / (82 + 83) = 7 (points)

What is the trajectory of a point whose distance to the origin is equal to 1

A circle or sphere of radius one
A plane is a circle. That's the definition of a circle
Space is a ball. That's the definition of a ball

Ten factoring problems in Mathematics

(1) 6x4y2－12x3y＋27x2y3
=3x2y·2x2y－3x2y·4x＋3x2y·9y2=3x2y(2x2y－4x＋9y2)
(2)－x4y＋x3y2－x2y3=－(x4y－x3y2＋x2y3)
=－(x2y·x2－x2y·xy＋x2y·y2)
=－x2y(x2－xy＋y2)
(3)xn＋3xn－1＋xn－2=xn－2·x2＋xn－2·3x＋xn－2·1
=xn－2(x2＋3x＋1)
(4)5(x－y)3＋10(y－x)2=5(x－y)3＋10(x－y)2
=5(x－y)2(x－y＋2)
(5)m(5ax＋ay－1)－m(3ax－ay－1)
=m[(5ax＋ay－1)－(3ax－ay－1)]
=m·(5ax＋ay－1－3ax＋ay＋1)
=m(2ax＋2ay)=2ma(x＋y)
(6)x2＋14x＋49=x2＋2·x·7＋72
=(x＋7)2
(7)(m＋n)2－6(m＋n)＋9=(m＋n－3)2
(8)－3ax2＋6axy－3ay2=－3a(x2－2xy＋y2)
=－3a(x－y)2
(9)(x2＋4)2＋8x(x2＋4)＋16x2
=(x2＋4)2＋2·(x2＋4)·4x＋(4x)2
=(x2＋4＋4x)2
=(x＋2)4
(10)64m2n2－(m2＋16n2)2
=(8mn)2－(m2＋16n2)2
=(8mn＋m2＋16n2)(8mn－m2－16n2)
=(m＋4n)2[－(m－4n)2]
=－(m＋4n)2(m－4n)2

The general trend of China's population change is increasing, so the per capita cultivated land area is gradually decreasing, right

The per capita cultivated land area includes two factors, one is the population factor, the other is the cultivated land area. Your question only refers to the population factor, not the cultivated land area, so it is wrong. It should be that the general trend of population change is increasing, and the total cultivated land area is shrinking, resulting in the per capita cultivated land area decreasing

A physics calculation problem, physics experts help ah. I want to calculate the formula and process. I add 50 points!
The LPG value is 3.5 × 10 ^ 7J / kg, the LPG stove burns 0.08kg LPG, the LPG stove burns 0.08kg LPG, and the water with 5kg mass and initial temperature of 20 ℃ is heated to 100 ℃
1. Heat absorbed by water
2. Energy conversion efficiency of cookers
I want to calculate the formula and process

(1) Q = △ t = 4.2 * 10 ^ 3j / (kg · C) × 5kg × (100-20) = 1.68 × 10 ^ 6J
(2) η = w useful / W total
Wtotal = 3.5 × 10 ^ 7J / kg × 0.08kg = 2.8 × 10 ^ 6J
η=1.68×10^6j÷2.8×10^6j×100％=0.6=60％

There are four Thursdays and five Wednesdays in June of a certain year. What day is children's day on June 1 of this year?

It was Tuesday at 6.1
6.2 6.9 6.16 6.23 6.30 are all Wednesdays, 6.3 6.10 6.17 6.24 are all Thursdays

Chemical formula in the first half of the third semester of junior high school

1、 Properties of oxygen: (1) reaction between elemental and oxygen: (compound reaction) 1. Combustion of magnesium in air: 2mg + O2 = ignition = 2MgO 2. Combustion of iron in oxygen: 3Fe + 2O2 = ignition = Fe3O4 3. Heating of copper in air: 2Cu + O2 = heating = 2CuO 4. Combustion of aluminum in air: 4Al +